Modern Day Alloys: The Transition from Magnesium to Aluminium

The automotive industry is certainly one where money talks, although when it comes to the wheels most car enthusiasts are more inclined to invest. This is probably what separates the typical driver from the car fanatic; with the latter almost always opting for alloy wheels.

While most of these drivers do this from an aesthetics perspective, it won’t come as any surprise to hear that these metal components do bring performance advantages as well.

When they were initially developed, magnesium was the metal of choice. Now, the industry has progressed to focus solely on aluminum and unless you deal in classic cars, it’s rare you’ll spot any vehicle fitted with ones of the magnesium variety.

How exactly did this happen? During the early days of alloy wheels, magnesium was the only metal utilized. They were immensely popular during the 1960s, but in some ways they became a victim of their own success. They were a die-cast wheel although as more and more vehicles started to take advantage of them, their frailties started to become more obvious.

However, we’ll first revert to just why these wheels were used by manufacturers. They are incredibly light, even when compared against aluminum, which prompts some huge advantages from a speed and efficiency point of view. They also happen to manage heat a lot better and this meant that there were no problems of the breaks overheating – which can sometimes happen if you use alloys of a different material. Let’s also not forget the aesthetics – magnesium has always looked great, although it took a few years before people realized that these enhanced looks came at a price, as we’ll now get into.

Cracks soon began to show with magnesium – and this doesn’t necessarily revolve around a figure of speech. Over time, many “mag wheels” started to crack and corrode, even though they had been fitted to some cars just several months ago. The fact that it didn’t react well to moisture just compounded the problem and in the end, these alloys required far too much maintenance. Finally, it also happens to be one of those materials that is hugely difficult to extinguish if it does set alight, meaning that manufacturers decided that it wasn’t suited to modern day cars.

In its place has come aluminum. Some would suggest that this doesn’t look quite as sleek on the eye, although advancements in technology mean that this is always being improved.

This is a material which does cost more, but also offers considerably more durability. Aluminum alloy wheels are much stronger than their magnesium alternatives, although this has only arrived following years of work. Initially, when magnesium alloys were first used, aluminum performed even worse.

Even though aluminum is the most widely used material when it comes to modern day cars, don’t think that magnesium has been completely discarded. It’s not been unheard of for some alloys to be formed of both metals, as manufacturers attempt to maximize the benefits from each option. However, from a general point of view, aluminum has won this battle hands-down.